The National Kidney Foundation estimates that each year more than half a million Americans go to emergency rooms for kidney stone problems. But what are kidney stones?
Urine contains many dissolved minerals and salts from which kidney stones form. These hard deposits of mineral accumulate on the lining of the kidneys. Every part of your urinary tract is susceptible. Some stones stay in the kidney and do not cause issues. Others may move from the kidney to the ureter (the tube that connects the kidney to the bladder). If the stone reaches the bladder, it can be passed out of the body in urine. If the stone gets stuck in the ureter, it blocks urine flow and causes kidney pain. Kidney stones can start small like a grain of sand but grow larger in size, even as large as a golf ball.
Signs of Kidney Stones
A kidney stone causes symptoms when it moves around within the kidney or passes into your ureter.
Common symptoms of kidney stones include:
- Severe pain in the back and side just below the ribs
- Pain in the lower abdomen and groin
- Waves of pain that differ in severity
- Pain when urinating
- Brown, red, or pink urine
- Pungent urine
- Cloudy urine
- Nausea and vomiting
- Constant urge to urinate
- Unusually frequent need to urinate
- Fever and chills
- Minimal urination
Types of Kidney Stones
There are different types of kidney stones. Here is the list, based on causes:
- Calcium stones: This is the most common type of kidney stone, and it usually occurs in the form of calcium oxalate. Oxalate is a substance found in food and also made by the liver. Diet, high doses of vitamin D, intestinal bypass surgery, and several metabolic disorders can increase the level of calcium or oxalate in urine. Calcium oxalate stones can also occur in the form of calcium phosphate—more common in metabolic conditions, such as renal tubular acidosis, or in people who take certain seizure medications.
- Struvite stones: Struvite stones may occur if there is an infection in the urinary tract. These stones can grow quickly and become quite large.
- Uric acid stones: Uric acid stones may occur in people who do not drink enough fluids or lose too much fluid. Certain genetic factors also may increase the risk of developing uric acid stones.
- Cystine stones: This type of stone may occur in people with a hereditary disorder that causes the kidneys to excrete too much of certain amino acids (cystinuria).
Diagnosing Kidney Stones
Doctors typically check for kidney stones with blood tests to measure the levels of calcium and uric acid in your blood. Blood tests can also help identify underlying medical conditions.
Imaging tests such as X-rays of the urinary system, an ultrasound, CT scan, or intravenous urography allow your health care provider to see the smallest of kidney stones in your urinary tract.
A urine test collected over a 24-hour period can help physicians figure out if you're excreting too many or too few stone-forming substances. Your doctor will also analyze the stones you've passed to determine the makeup of the stones and their causes, and to develop a treatment and prevention plan.
What Causes Kidney Stones?
Kidney stones usually do not have a specific cause, but several factors may increase the risk of developing this condition. Some people’s urine may lack substances that prevent minerals from sticking together, creating an ideal environment for kidney stones to form. Risk factors include:
- Personal or family history: If someone in your family has kidney stones, you may be at risk of developing this condition. And if you have already had one or more kidney stones, you are more likely to develop another.
- Dehydration: Drinking water dilutes the substances that may form stones in the urine, so make sure you stay hydrated. If you do not drink enough water and you live in an area with a warm climate or sweat a lot you may be at higher risk.
- Diet: A diet rich in sodium (salt) and sugar may increase your risk of some types of kidney stones. One of the more common causes of calcium kidney stones is high calcium levels in the urine. Reduce your salt consumption to lower urine calcium—too much salt in your diet increases the amount of calcium your kidneys must filter and ups the risk of kidney stones.
- Obesity: Overweight people may be at risk of developing kidney stones. Large waist size and weight gain have been linked to this condition.
- Bowel conditions: Gastric bypass surgery and gastrointestinal diseases can affect the absorption of calcium and water, increasing the buildup of minerals in the urine. Diarrhea may result in loss of fluid, lowering urine volume. The body may also absorb excessive oxalate from the intestine, resulting in more oxalate in the urine.
- Low urine volume: Kidney stones can block the flow of urine. When urine volume is low, urine is concentrated and dark in color, signaling that there is less fluid to dissolve salts. Low urine volume may come from dehydration, hard exercise, or working or living in a hot place.
- Medical conditions: Conditions that may increase the risk of developing kidney stones include renal tubular acidosis, high blood pressure, cystinuria, hyperparathyroidism, certain medications, and some urinary tract infections (UTIs).
- Some medications: Some medications, and calcium and vitamin C supplements, may increase your risk of developing stones. Tell your doctor all the medications and supplements you take, as they could affect your proclivity for stone formation.
Kidney Stone Treatments
Treatment for kidney stones depends on the type and the cause.
- Passing a kidney stone: The stone gets expelled naturally through the urine. You may be able to pass a small stone by drinking 2 to 3 quarts (1.9 to 2.8 liters) of water a day. The process of passing a small stone can cause discomfort, so consider taking pain relievers such as ibuprofen (Advil).
- Medications: The doctor may give you a medication, known as an alpha blocker, to help pass your kidney stone. There are other medications that can be prescribed depending on the kind of kidney stones you have. Examples include a thiazide diuretic or a phosphate-containing preparation to prevent calcium stones.
- Percutaneous nephrolithotomy (PCNL): Using PCNL, the physician will insert a tube through a small incision to help drain the kidney.
- Kidney stone removal: Surgery may be performed if the stone fails to pass, the pain is too great to wait, or the stone is affecting kidney function. Bigger and painful kidney stones can be removed with different procedures. A common procedure called extracorporeal shock wave lithotripsy (ESWL) uses sound waves to break up stones. Very large kidney stones can be removed using small telescopes and instruments inserted through a small incision in your back, or using a scope.
Kidney stones may put you at higher risk of chronic kidney disease. The following tips can help you naturally prevent kidney stones from recurring.
Doctors usually recommend drinking 8-16 ounces every hour. If you live in a hot, dry climate or you exercise frequently, you may need to drink even more water to produce enough urine. Check your urine to make sure you drink enough water—if is light and clear you are on the right path.
Reduce foods rich in oxalates such as rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate, black pepper, and soy products. Reduce the amount of salt you eat—consider adding spices to add flavor to your dishes. Eat plenty of sprouted grains because they lower levels of phytic acid, and consume foods high in magnesium like avocados and bananas. Limit the amount of animal protein you eat, because meat such as poultry, seafood, and red meet raises uric acid levels, which can increase kidney stone development.
Go the extra mile when hydrating.
- Lemons contain citrate, which is a chemical that prevents calcium stones from forming, so feel free to add fresh squeezed lemon to water anytime you like.
- Use fresh or dried basil leaves to make a tea or add basil to a smoothie—basil contains acetic acid, which helps to break down the kidney stones and reduce pain and the risk for future stones.
- Apple cider vinegar contains citric acid, which can help dissolve kidney stones. Add 2 tablespoons of apple cider vinegar to 6–8 ounces of purified water. Do not consume more than one 8-ounce glass of this mixture per day.
- The broth from cooked kidney beans helps improve kidney health and helps flush out the stones. Strain the liquid from cooked beans and drink a few glasses throughout the day.